A multi-chip package (hereinafter called MCP) for storing the plural semiconductor chips to one package has merits in that cost is reduced by combining chips formed by device processes of different kinds and forming one package, and memory capacity can be simply increased by combining plural memory devices, etc. Further, in IC, the number of signal terminals exposed to the exterior of the package is limited by a package size. Namely, the number of terminals able to be arranged is determined in accordance with the length of each side in a plastic package of a rectangular shape.
Such a semiconductor integrated circuit generally has many functions. Accordingly, there is a tendency in which the number of signal terminals is also increased. Therefore, the limit of the number of terminals able to be arranged tends to become a problem. With respect to signals transmitted between plural chips, inter-chip wiring for connecting both signal terminals in the package interior is performed. However, with respect to a pad (signal terminal) in which the inter-chip wiring is performed, it becomes difficult to inspect electric characteristics in a package state (MCP state). Therefore, it is necessary to cope with this problem by arranging a special construction so as to make these inspections.
As mentioned above, for example, there is a semiconductor device disclosed in U.S. Pat. No. 6,885,212 as a technique for making the inspection with respect to the signal terminal in which the inter-chip wiring is performed. As shown in FIG. 4, this semiconductor device respectively has switch portions SW0, SW1, SW2, . . . between a common line LO and signal terminals constructed by a probe terminal P0 connected to an external terminal and plural non-probe terminals P1, P2, . . . not connected to the external terminal. This semiconductor device is constructed so as to arbitrarily select a measuring object terminal from the plural non-probe terminals by a combination of conducted switch portions.
For example, when the non-probe terminal P1 is inspected, switch portions SW1 and SW0 corresponding to this terminal P1 and the probe terminal P0 are conducted and both these terminals are connected. Thus, the characteristic inspection of the non-probe terminal P1 is made through the probe terminal P0.
Namely, the above construction corresponds to an input-output compression test for commonly inputting and outputting a test signal through the probe terminal P0. A signal inputted to one of the non-probe terminals P1, P2, . . . is also commonly inputted to the probe terminal P0. Accordingly, for example, when the inspection is made with respect to the non-probe terminal P1, cases in which a set input voltage range is different from that of the probe terminal P0 and an input level to the probe terminal P0 becomes an intermediate electric potential if the non-probe terminal P1 has an analog input, are supposed. Thus, a through electric current is generated in an input buffer I0 connected to the probe terminal P0, and a problem of reliability for a long period and a problem unable to accurately inspect the non-probe terminal P1 are considered.